In recent years, wireless communication provides not only voice communication but also various services such as access to the Internet, delivery of streaming broadcasts, and delivery of contents containing music and videos.
In order to provide these services anywhere with high quality, introduction of a relay station that relays communication between a terminal and a base station is studied in LTE (Long Term Evolution) Advanced, which is a next-generation standard of 3GPP (3rd Generation Partnership Project). The high-quality service here refers to, for example, a service that is provided to a wide connection area with high throughput.